Cellulases are utilized, based on their properties, in various industrial fields, particularly the field of fabric processing. In this field, a cellulose-containing fabric is treated with cellulose to impart desired properties to the fabric. For example, a treatment with cellulose is carried out to improve the touch and/or appearance of cellulose-containing fabric, or for a “biowash” which imparts a “stonewash” appearance to a colored cellulose-containing fabric, thereby providing the fabric with localized color variations. Further, in the process for manufacturing lyocell, cellulase is used for removing the fuzz generated in the process from the fabric surface. In this connection, lyocell is a regenerated cellulose fabric derived from wood pulp, and has recently attracted attention for properties (such as high strength or water absorption) and as a production process that causes less environmental pollution.
Hitherto, it has been considered that cellulase decomposes cellulose by the synergistic effect of plural enzymes. Because of an evolution of protein separation techniques or genetic engineering techniques, an attempt has been carried out to separate enzyme components appropriate for fabric processing from cellulase consisting of plural enzymes, and to produce the enzyme components. Particularly, cellulases derived from microorganisms belonging to filamentous fungi such as genus Trichoderma or genus Humicola have been subjected to serious study. For example, as cellulase components, CBH I, EG V, NCE4, and NCE2 in genus Humicola, and CBH I, CBH II, EG II, and EG III in genus Trichoderma were isolated, and thus, cellulose preparations containing as the major components one or more specific cellulose components appropriate for each purpose can be produced by preparing overexpressed enzymes or monocomponent enzymes using genetic engineering techniques.
Further, it is known that endoglucanase enzyme NCE5 is useful in imparting a stonewash appearance to stained cellulose containing fiber or improving the touch thereof, as a cellulase which causes a slight redeposition or backstaining (i.e., a slight back staining) of an indigo dye to clothing during the treatment (see patent reference 1).
In another aspect, when cellulases are used as a detergent for clothing, not only a quantitative improvement of cellulose components used but also a qualitative one is desired. More particularly, a detergent for clothing contains various surfactants, and a solution obtained by solubilizing the detergent for clothing in water is alkaline (pH10 to pH11). Therefore, it is necessary that cellulases contained in a detergent for clothing should be resistant to various surfactants, and exhibit a strong activity under alkaline conditions.
(patent reference 1) International Publication WO01/90375 (pages 2-3, and the sequence of SEQ ID NO: 1 in the Sequence Listing)